Circulation system for pulp digesters



Oct. 21, 1930. E. MORTERUD 1,779,233

CIRCULATION SYSTEM FOR PULP DIGESTERS Filed -Nov. 14, 1928 Patented Oct. 21, 1930 PATENT OFFICE EINAR HOBTERUD, OI TOBDEROD, Km MOSS, NORWAY CIRCULATION SYSTEM FOR PULP DIGESTEBS Application filed November 14, 1e28, Serial No. 819,390, and in Norway December 28, 1927.

In the process of digesting pulp it is well known that it is necessary to circulate the digester liquor in order to establish even temperature conditions so as to obtain throughout the pulp charge the best conditions for releasin and dissolving the incrustations.

en the circulation takes place through a pump on the outside of'the digeste'r,'it is known to provide the circulation conduit with a valve arrangement adapted to reverse the direction of circulation, whilst maintaining the direction of rotation of the pump.

It has also been suggested to mount the circulation pump inside the digester in order -to obtaina cheap, valveless arrangement.

This arrangement of the pump inside the digester, however, has the drawback ofnot permittin reversion of the direction of circulation. he arrangement of valves which will'enable the direction of circulation to be reversed is out of question for practical rea-.

' sons when the pum is mounted inside the digester, and in or er to obtain the advan 'tages of the pump arrangement inside the ing theadvantages of reversible circulation,-

the digester is provided in accordance with the present invention with a reversible circu lation pump mounted inside the digester and provided with a conduit leading to the to of the digester, and another leading to the ttom t ereof, each of said conduits being adapted to act as intake and outlet tube respectivel according to the direction of rota tion of t e pump. Y Both conduits consequently are provided with sieves or screens in order to prevent pulp from entering into the pump. Y

The accompanying single figure shows one formof the invention.

On the inside of the digester shell 1 there is mounted irreversible amp 2 of any conventional type adapted to tions by means of an. exterior traon element 3, such asa pulley or the like.

The auction and pressure tubes respectively 4 and 5 of the pump 2 are both provided wit "sievearran ements 6.

During t e rotation direction tube 5 will act as suction and tube 4 entering that tube which is acting as t of the pump in'one as pressure pipe, and the circulation will follow the arrow 1.

When the pump rotates in the opposite direction, tube 4 W111 be suction pipe and tube 5 pressure pipe, and the circulation will 01- low the arrows 11.

Claims. 1 1.- In a pulp digester a reversible circula- I tlon pump mounted inside the digester, circulation tu es leading from said pump to the top and bottom respectively of the-digester and screens covering the outlet openings of said circulation tubes into the digester in order to prevent wood pulp from entering the tube which is acting as suction tube to the o5 pump. 2. In a pump digester, means for producing a reversi le circulation, said means being comprised substantially entirely of a reversible circulation ump mounted inside the digester, circulationv tubes leading from said pum to the top and bottom respectively of the igester, and screens coverin the outlet openings of said circulation tu into the dlgester in order to prevent wood pulp from 7 e suction tube of the pump. 7

In testimony whereof I .aifixmysignature.

EINAR MORTERUD.

driven in both direc- 

